This invention relates to chill-proofing beverages such as beer while preventing contamination of the beer with metal ions. The invention involves a combination of chill-proofing agents and an amorphous magnesium silicate.
The term "beer" as used throughout this specification and the claims encompasses all types of malt beverages. Such beverages include, but are not limited to, lager, pilsner, Dortmund and Munich beer, as well as top fermented beverages such as ale, porter and stout.
Turbidity is an important and troublesome problem encountered in brewing operations and can be of biological or physico-chemical origins. Gross turbidity effects are overcome by filtering and/or other physical methods. Secondary and more subtle turbidity problems involve the haze which develops on aging and/or chilling the beer. This haze is caused by the coagulation of certain organic materials in the beer. Numerous inorganic and organic substances can be used to adsorb the materials that combine to form the haze so that they can be separated from the beer prior to packaging. Organic adsorbents may contain factors that are dissolved in the beer so that they are often rejected. Inorganic adsorbents and filter aids, often siliceous materials of high surface area, are effective in reducing or eliminating chill haze, but they may contail small quantities of metals that are soluble in beer and contaminate it. Such dissolved metals may de-stabilize colloidal constituents of beer, inducing lower quality. High dissolved iron levels affect beer quality and shelf life.
A number of inorganic adsorbents are used with filter aids in processes to remove materials that cause chill haze. Silica hydrogels and xerogels, calcium aluminum and magnesium silicates, diatomaceous earth, several types of natural minerals and clays and mixtures thereof have been suggested and used as chill-proofing agents. U.S. Patents that disclose such art include U.S. Pat. Nos. 3,163,538; 3,251,693; 3,436,225; 3,617,301; 3,940,498 and 3,958,023. Nearly all these materials originally contain metals or would pick up metals, particularly iron, during processing. At least a portion of these metals can be dissolved in beer, which is mildly acid, resulting in a loss of quality.
Bradley and McAdam, in U.S. Pat. No. 4,134,857, discuss the beer or beverage soluble-iron problem in connection with filter aids. Their solution to the problem is to treat the iron-containing materials with certain organic acids that dissolve out the iron that is soluble in beer. We believe this approach to be only partially successful in treating inorganic chill-proofing agents such as silica hydrogel while being rather expensive.